1. Field of the Invention
The present invention relates to door locks. Conventional door locks are easily picked or sawed or allow the door to be jimmied, thus leaving the occupant vulnerable to thieves or other intruders who seek forceable entry. Picking is the act of inserting a thin piece of metal through the space between the door and door jamb and manipulating the lock until it is opened. It is desirable for the thief to be able to see the lock he is picking from the outside. Jimmying is the act of forcing a door open by prying it laterally with a crowbar or like implement. Sawing is performed by inserting a thin blade between the door and door jamb and sawing through the lock.
Specifically, the present invention relates to a high security, keyless door lock which is substantially pick-proof, saw resistant, tamper and jimmy proof. The door lock is attached to the door and the door frame. A horizontal crossbar is held in place by a pin which in turn is held in place by locking channels in a keeper. The lock is quickly and simply installed in an apartment, residence, business, or any other place where it is desired to secure a door from the inside.
2. Description of the Prior Art
Door locks of the crossbar type have been employed for many years and were even used in frontier times simply as a bar across the gate of a fort. Over the years, various improvements have been made to crossbar locks. However, none of these improved crossbar locks appear to fully meet the needs of the modern urban dweller who, in these days of high crime, requires a strong lock which is substantially pick-proof, jimmy-proof, and saw resistant while at the same time being inexpensive, easy to install, and easy to open in the event of an emergency such as a fire.
An example of a prior art device including a crossbar type lock is shown in U.S. Pat. No. 1,351,117. Therein the crossbar type lock is used in combination with a conventional door lock with movement of the pin of the crossbar type lock being controlled by a pivotal cam device which is engaged by the lock bolt of the conventional door lock. When the conventional lock is closed, the lock bolt engages the cam device which in turn engages the pin end and projects it into an aperture to secure a horizontal member across the door to aid in inhibiting entry. When the lock bolt is opened, the cam device and therefore the pin drop due to gravity, freeing the horizontal member and allowing the door to open, thus, picking or jimmying of the conventional door lock will result in release of the crossbar type lock.
The use of pins as coupling means is well known in the art, see U.S. Pat. No. 299,083. Such coupling pins are employed, e.g., for the connection of a cutting bar of a harvester to its pitman. Exterior car door fasteners employing removable pins are also known for use in preventing sliding doors such as the doors of railroad cars from opening, see U. S. Pat. No. 1,165,013.
In using the pin constructions of U.S. Pat. Nos. 1,165,013 and 299,083, two hands are required to either couple or uncouple the devices thereby rendering them undesireable for possible use in a security door lock since ease of opening or closing of the lock from the inside is important to allow quick evacuation of the premises in the even of an emergency, such as a fire, and to enable the lock to be readily closed when one hand is occupied, for example, with a bag of groceries.